This relates in general to techniques for endotracheal intubation known as laryngoscopy, and more particularly, to instruments for performing laryngoscopy known as laryngoscopes.
The use of laryngoscopy for placing a tube in the trachea has been practiced since the end of the last century. Since that time, the search for improved methods and instruments for intubation has continued.
An early laryngoscope developed by C. Jackson had a U-shape. In 1913, Janeway designed an L-shaped instrument with a blade having a slight curve at the end, and with batteries in the handle. In 1941 R. A. Miller described a laryngoscope blade with a smaller tip than those commonly used at the time, and with a curve which began about two inches from the end. In 1943, R. R. McIntosh developed a blade curved along its entire length. In 1973, a blade was developed by 0. C. Phillips which combined the curved tip of Miller and the shaft of the Jackson blade. More recently, in 1988, C. P. Bellhouse developed an angulated laryngoscope which includes essentially a straight blade modified by bending forward through 45 degrees at the midpoint. Because the angle of this blade may obscure the view of the entire larynx, a flange is provided to enable a prism to be fitted flush to the laryngoscope blade to enable the user to see around the corner. However, this makes less room available for intubation, and increases the potential for damage to the teeth.
Still today, there are patients for whom intubation is either difficult or impossible with available techniques.
Accordingly, it is the principal object of this invention to develop an improved blade or spatula that makes both visualization of the larynx and intubation possible in the most difficult cases and for the widest spectrum of patients.
Another object is to provide a blade or spatula which is incrementally curved to lift the epiglottis and reduce the need to tilt the laryngoscope posteriorly.
Still another object is to provide a blade or spatula which has a wide flat surface to allow easy handling of the tongue and epiglottis.
Another object of the invention is to provide a laryngoscope which is easy to handle and to clean.
These and other objects are achieved in a laryngoscope having a double-angle blade or spatula. In a preferred embodiment, the latter blade is 3 millimeters thick, 21/2 centimeters wide at its proximal end which is coupled to the handle. The blade or spatula has three segments lengthwise. The first segment extends in a direction substantially normal to the handle to a first bend, at which the blade or spatula is bent inward toward the handle through an angle of 20 degrees. This forms a second segment which extends 5.4 centimeters in a new direction to a second bend inward through an angle of 30 degrees, forming a third segment which extends 2.6 centimeters to the distal tip.
A particular feature of the laryngoscope of the present invention is a small cylindrical bulb superposed adjacent and parallel to the top edge near the end of the second segment. This is connected by a wire or optical fiber running along the side of the blade or spatula to the handle, where batteries are stored.
Particular advantages of the double-angle laryngoscope of the present invention is that:
(a) it allows more room for intubation;
(b) it decreases potential for damage to the Patient's teeth;
because the spatula or blade has two incremental curvatures;
(c) it improves lifting of the epiglottis;
(d) it reduces the need for the operator to tilt the laryngoscope posteriorly during the procedure;
because the spatula or blade has a wide and flat surface;
(e) it allows easy handling of a big tongue nd epiglottis;
because of its simplicity;
(f) the laryngoscope of the present invention is easy to handle and easy to clean.
Other objects, features and advantages of this invention will be better understood from a detailed study of the specification and claims hereinafter with reference to the attached drawings.